The question of whether or not there are cracks on the seafloor of the Gulf of Mexico surrounding the BP Gulf Oil Spill is no longer a matter of debate.

A report filed with the MMS by BP reveals that BP first encountered cracks in the seafloor as far back as February providing clear proof that BP and the Federal Government has known about the cracks all along.

It took BP ten days to seal those cracks initial cracks.

As BP continued to drill the well more cracks formed in the surrounding rocks which further complicated the drilling operation during the ensuing weeks.

Those fissures in the seafloor have the potential to allow explosive releases of natural gas to rush up the shaft.

As one Geologist over at The Oil Drum explains:

Good grief! looks like TOD has been infected by a bunch of reservoir engineers. There goes the neighborhood. Not that’s really a bad thing. Now I’ll offer the geologist explanation of centroid and thus would be easily understood by the non-nerds (a term I use with great affection, of course). The pressure in the sealing shale is different than the reservoir pressure. And the pressure in the reservoir varies laterally. The higher on the structure the higher the reservoir pressure. The centroid is that spot where the shale pressure and the reservoir pressure are equal. Unfortunately we don’t have enough details to tell where the blow well falls exactly.

Here’s the problem that can develop: if the oil/NG column is very high the pressure in the top of structure in the reservoir may be very close to that in the sealing shale. Perhaps just 0.2 ppg difference. Here’s the risk: if a well cuts such a small pressure differential the it would take a slightly higher STATIC ( mud pumps turned off) to control well flow. But when drilling the pumps add effective pressure to the mud mimicking a higher mud weight. This is the ECD (effective circulating density). So this is the worse case scenario: the reservoir pressure is 12.6 ppg and the shales fracture at 12.9 ppg. So you pump in 12.8 ppg mud. But the ECD adds pressure so while drilling the ECD is 13.1 ppg…sufficient to fracture the shales. So if they start to lose circulation from this fracturing they need to cut the mud weight back to an ECD of 12.8 ppg. But when the turn the pumps off to pull drill pipe out of the hole they lose ECD and the static mud weight becomes 12.4 ppg. This allows the reservoir to flow since it’s pressure is 12.6 ppg. There have been wells drilled in the DW GOM where they couldn’t remove the drill pipe from the hole: Turn the pumps off and it tries to kick you. Leave the pumps on and you lose mud. Some of these wells had to have cmt pumped to kill and abandon the hole.

So far I haven’t seen enough info to guess if the RW might run into such a problem But based upon the pore pressure plot BP put out I’ll guess it won’t be a problem. But that’s based upon a lot of assumptions including where the wild flow is going and the condition of the csg and other cmt shoes.

The differences in pressure referred to in the comment are representative of the complication that BP faces from natural formations found in the seafloor.

The presence of the fissures in the surrounding strata only further compounds the problems.

Any of these of these cracks could contain a pocket of higher pressured natural gas or a even a large loss of pressure where the crack leads to the surface on the seafloor.

It Was Greed, Not Cutting Corners To Save Cost, That Caused The Oil Spill

The Federal Government is playing PR for BP by repeatedly claiming that BP cut corners to save cost.

BP should have killed the entire operation when it found out about the cracks.

Robert Bea, an engineering professor at the University of California, Berkeley said “The incident was a show stopper. They damn near blew up the well.”

In fact it has now been revealed that BP reported to the Government that the well blew out in March, but BP was able to get the blowout under control.

In the latest round of Congressional Hearings a letter sent to Tony Hayward pointed out 5 incidents where BP cut corners to save money.

One of the issues highlighted is that BP chose not to cement the final 1000 feet of the well leading into the reservoir which was in direct violation of MMS regulations which require the final 500 feet of the well connecting to reservoir to be cemented.

The letter also points out that instead of running a liner and a tie back BP chose to run a single string of pipe.

BP also did not did perform a cement log to make sure that the cement bonded correctly,  did not install a sleeve to seal the well to reservoir, and BP did not fully circulated the mud during the drilling process to make sure there where not pockets of gas in the well.

While all of those incidents where blatant disregards of best practices and/or safety regulations  the reason BP skipped those steps wasn’t due to cost cutting measures.

After reading the PPFG Plot that congress released a user at the oil drum claiming to be a petrophysicist points out that BP was just losing mud down the well because of a pressure differential.

This implies that BP was at a point where a critical decision needed to made.

If BP were to follow regulation it means they had to shut down the well because cementing the last 500 feet of the well according to regulation would have rendered the well unusable.

The other option was to take the risk of running the single string in exchange for the possible reward of tapping the largest oil reservoir ever found in our hemisphere.

BP chose to run the single string it couldn’t possible follow thought with the other points that congress pointed out.

As another member of the The Oil Drum puts it after viewing the plot:

I had heard this document was out there, but hadn’t seen it until now. Nice to finally have an actual electric log to look at. The sets of curves to the right of the depth track – these are the resistivity curves, and tell us things that the fancy curves put up elsewhere in the document try to quantify: The pore pressure of the shales is changing throughout the section. They were drilling from a high pressure zone to a slightly lower pressured zone. They’ve put some numbers on it, with a 14.1# sand at 17,700′ and the main pays having a mud weight equivalent to 12.6#. This is totally believable.

In a previous response, I put up a cartoon that talks about this, looking at it a bit differently. The way that the old men look at it, is the shales are sealing off zones of lower pressure. The lower pressure zone in this case is the one that is flowing out all into the Gulf of Mexico. So, it’s not as low pressure as you would think.

What it does mean, is that the higher pressure sands (and shales), combined with a lower pressure pay section, forced BP to try to get away with a lower amount of cement coverage. To properly protect the well with cement, the weight of the cement sufficient to isolate the pay properly would probably have screwed up the pay sands themselves — they would have limited the productivity of the eventual completion. It was a gamble with horrible results we’ve all seen.

This is why BP and others think the oil/gas is coming up around the outside of the casing — at least it was initially.

At least now I can guess where they’ll try to intersect the wellbore.

I have the electric log. Now I want the deviation plan for the relief wells. Anybody got that?

The corporate greed of BP won the battle and now we all know the results of that fateful decision.

From Bloomberg News

BP Plc was struggling to seal cracks in its Macondo well as far back as February, more than two months before an explosion killed 11 and spewed oil into the Gulf of Mexico.

It took 10 days to plug the first cracks, according to reports BP filed with the Minerals Management Service that were later delivered to congressional investigators. Cracks in the surrounding rock continued to complicate the drilling operation during the ensuing weeks. Left unsealed, they can allow explosive natural gas to rush up the shaft.

“Once they realized they had oil down there, all the decisions they made were designed to get that oil at the lowest cost,” said Peter Galvin of the Center for Biological Diversity, which has been working with congressional investigators probing the disaster. “It’s been a doomed voyage from the beginning.”

…

On Feb. 13, BP told the minerals service it was trying to seal cracks in the well about 40 miles (64 kilometers) off the Louisiana coast, drilling documents obtained by Bloomberg show. Investigators are still trying to determine whether the fissures played a role in the disaster.

…

The company attempted a “cement squeeze,” which involves pumping cement to seal the fissures, according to a well activity report. Over the following week the company made repeated attempts to plug cracks that were draining expensive drilling fluid, known as “mud,” into the surrounding rocks.

BP used three different substances to plug the holes before succeeding, the documents show.

“Most of the time you do a squeeze and then let it dry and you’re done,” said John Wang, an assistant professor of petroleum and natural gas engineering at Penn State in University Park, Pennsylvania. “It dries within a few hours.”

…

Gas Surges

On March 10, BP executive Scherie Douglas e-mailed Frank Patton, the mineral service’s drilling engineer for the New Orleans district, telling him: “We’re in the midst of a well control situation.”

The incident was a “showstopper,” said Robert Bea, an engineering professor at the University of California, Berkeley, who has consulted with the Interior Department on offshore drilling safety. “They damn near blew up the rig.”

PS. Was anyone recording Ocean Intervention III – ROV 1 (44287) at 5:30 this morning?